


Rifttale

by Epithepeppy1997



Category: Undertale (Video Game)
Genre: Action Figures, Alternate Universe - Science Fiction, F/F, Family Drama
Language: English
Status: In-Progress
Published: 2019-10-13
Updated: 2019-10-15
Packaged: 2020-12-14 19:10:17
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,730
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21020813
Author URL: https://archiveofourown.org/users/Epithepeppy1997/pseuds/Epithepeppy1997





	1. Prologue/ Chapter 1 Horrortale

This AU takes place 19 years after the barrier is broken. The monsters have made peace with the humans after a legal struggle. Sans and Toriel have had 2 children, Astelle and Gabriel. Astelle is a gentle Boss monster who spends her time in the books and in the dojo. She trains with her mother and Undyne daily on how to fight and help others. Her brother Gabriel is a different story. Gabriel is an upbeat & punny skele like his father, only twice as tenacious. But the thing about Gabriel is, he hasn't discovered his magic power yet. And he's 19! Sans & Papyrus have been training him in hand to hand while a mature Frisk and Asriel have been training him in agility and dodging. (Note: Asriel & Gaster are present in this AU) One day Alphys and Gaster call the whole gang into the lab. Gaster has found anomalies in the space time continuum, ruptures between worlds that must be corrected in order to maintain balance. Alphys steps up and presents a watch-like portal device that will allow 3 people & 3 alone to travel between these AUs. At first, Frisk volunteers, then Toriel, then Papyrus. One by one everyone argued over who would go on this journey. Then Gabriel yells for everyone to shut it; and that he, Astelle, and Sans should go. Toriel tries to convince him not to go but to no avail. Sans promises her to keep them both safe. Astelle & Gabriel hug their mother and tell her that they will get home safe. Sans gets the rundown on how the device works from Alphys & shoots a portal to the 1st AU. So the journey begins.  
Sans & Astelle come out of the portal to a destroyed version of Snowdin, the watch says that thus AU is called Horrortale. Astelle notices that the whole place seems abandoned, almost. They were being watched. But something else was off,   
Gabriel was missing! Gabriel landed right outside the Ruins. He faced the door and gave it a knock, asking if anyone was there. After a few moments the door creaked open to reveal Horror Toriel who asked, "Are you here to kill me?" Gabriel says no and says that he is here to help. He was both frightened and sad to see his mother in such a poor state. Gabriel then asked what was happening in this world? Toriel told him that a human fell, killed a few particular monsters. MK, Alphys, & Asgore. Then left the underground. Toriel continues and says that she tried to come back to rule and enforce a human-friendly policy but is immediately overthrown by Undyne who took the crown, declared martial law, and labeled her an outlaw. Which confined her to the Ruins, where she has been slowly losing her mind through fear of death. Gabriel is disheartened by this information and takes his mother's hand. Horror Toriel asks Gabriel "Promise me I won't die here."  
Gabriel says   
"I promise to free you and rid Undyne of her twisted reign." He kisses her forehead and leaves. But as he left, something had awoken within him. a powerful surge within his soul. The power of HONOR. Gabriel's power has awakened. Meanwhile in Snowdin, Sans and Astelle are looking for clues as to why this AU is disrupted. Sans leads them to Grillby's for information. (Go figure)As they enter, Astelle notices a monster that looks just like Sans sitting in a booth in the back. He gets up and throws a twisted grin on his face. It was Horror!Sans, stepping toward her with an axe in his hand. "You look just like her" he says. Sans steps in front and says "Back up freakshow, or I'll show you just how scary I can be."  
Astelle pushes him away and easily aprehends Horror!Sans. "I can tell you're a little crazy but even a nut job like you will understand this. We're trying to help you. And it's not polite to murder the good guys, so cut the crap and tell us what the f@#k is going on!" says Astelle.  
Sans just stands there, feeling a little smaller now. Everything calms down and Horror! sits them both down and explains Horrortale to them. Sans reads the AU device again to find that another human was supposed to fall at this time. "Looks like we found our anomaly" says Sans.  
Astelle and Sans exit Grillby's to go and find Gabriel. Only to find Another individual that looks like Sans standing outside. It was Error!Sans.  
"Enjoying your visit? The name's Error, I hope you love what I've done with the place." he says.  
"What have you done with the human Stutters?!" Asks Sans.   
"Oh their dead, this universe in particular needed a cleanup. And you're next."  
Sans & Astelle prepare for a fight. Error tries his cables first, which Sans evades & Astelle burns with swift deflections. Error fires several Gaster blasters next. Which miss Sans but hit Astelle with minimal damage. After a few attacks of their own, Sans & Astelle force Error to retreat to the Antivoid. "We need to find Gabriel" says Sans.   
Gabriel finds his family just outside of the Capital of the underground. Astelle hugs him while Sans asks him "Where did you go?"   
"I was zapped to this big door in the middle of a forest, I was given the rundown by an alternate version of mom. She was in pain Dad; I have help her, all of them. Undyne has to pay."  
"Easy kiddo we're here to fix this place, not make it worse. Some glitchy fella killed the human that was supposed to fix this dump. So now we gotta do it. We have to break the barrier. But believe me, Undyne ain't getting off Scott free."  
They made their way to the throne room where Undyne sat with a spear clasped in her hands.  
"There should be a hole in your head Sans." she says. "I got better, the HOLE thing got fixed."(badumtss)   
Undyne angrily throws the spear at him. Gabriel catches it before Sans can even react. Then he snaps it in half with his bare hands. Gabriel's eyes begin to glow a neon green color. He forms a bone staff and engages Undyne with blinding speed. He strikes and strikes with Undyne hopelessly fighting back. Sans and Astelle watch as Gabriel dominate this fight.  
"He's.. unlocked his power. And he's super fast." says Astelle.  
" This energy is different from ours, I can feel it. He is much stronger than any of us. What kind of magic is this? His soul's color, it doesn't match any recorded energy hue I can think of."  
Gabriel eventually gets Undyne on the ground.and demands that she surrender. She agrees and stands down. As Gabriel turns away, Undyne throws a spear at him. She misses and grazes Astelle. Enraged, Gabriel punches her repeatedly in the face. Sans yanks him back and says "Stop Gabe! That's enough! She got what's coming to her just let it go!" Gabriel calms down and apologizes for his outburst.   
"You okay Sis?"says Gabriel. "Yeah, yeah I'm okay."   
"Let's go kids, we gotta finish this." Sans says.  
The trio leave Undyne knocked out cold on the floor and proceed to the barrier. Sans gthers the humans souls that are kept there.  
"Alright kids, since it's just us we're gonna need to give this everything we got. I'm gonna divert the soul power between us. Use your most powerful attacks." says Sans.  
"But dad, I don't have anything to use. Some bones won't exactly be enough." says Gabriel.  
"But now that you got your mojo you will. Son, it about time I taught you how to use the Gaster blaster."  
"OMG, yes! This is gonna be awesome. I'm flabbergastered."(badumtss)  
"Heh, good to hear it. Alright you have to draw the energy directly from your soul, extend your arm in the direction where you want to expel the power."  
Gabriel stretches his arm out toward the barrier and a Gaster blaster forms above him. He can barely contain his excitement.  
"Alright, let's do it." Sans says.   
He divides the power between the 3 of them and ordered them to fire their attacks directly at the barrier. Sans fires several Gaster blasters at once, Astelle releases a horizontal fiery vortex, and Gabriel shoots a large energy ball . Very different from that of a normal GB. (Gaster Blaster abbreviation) They keep up the push but are making little difference."I made a promise to set them free. And I intend, to HONOR IT!!" screams Gabriel.  
The energy ball he released grew to a much larger size and began boring into the barrier, it was coming apart  
"Keep it up bro, I believe in you!" says Astelle.  
"I'm rooting for you son, you got this!" says Sans.  
Gabriel continues to scream as they all give it one final push. CRRRRACK!!! The barrier is shattered. " We did it, we actually did it." said Gabriel."  
"We never doubted you for a second. Cmon let's give these poor souls the good news." said Sans.  
The trio began rounding up the entire underground to tell them of the barrier now being broken. Gabriel made a stop at the Ruins and personally escorted Horror!Toriel to the Surface. The whole Horrortale gang was there, staring off at the horizon. Undyne was in restraints by the newly formed Royal Guard. It's a miracle they didn't kill her on the spot. Other than that, things were looking up. Astelle & took a moment to see their good work as Sans said, "Cmon chums we're not out of the woods yet. There's still more AUs out there that need a fixing"  
"Right" Gabriel & Astelle say simultaneously. "Jinx!" they say as Sans forms a portal to the next AU. The trio hops through onto the next world.


	2. GZtale

After passing through the portal, Sans noticed something, "We're in the wrong place, coordinates were set for Underswap." he said.  
"We got a bigger problem, Gabe is gone. And there's some mean looking guys heading our way."  
stated Astelle.  
She was right, Gabriel was nowhere to be seen. In top of that, they both were being surrounded by mercenaries. "Alright meatheads, tell me where you stashed my son and you might not have such a bad time." said Sans.  
"Your son is now property of the king, brother."  
There stood this world's Papyrus; he was cold, hateful, and menacing compared to that of the normal one. "Kill them" says Papyrus.  
Gabriel woke up bound to a table in a dark room, with Asgore & Alphys standing over him  
" You know what needs to happen doctor, I expect results." said Asgore. "You are destined for great things Gabriel, your pain is the reward of all." As he departs, Alphys turns to Gabriel and says, "I'm sorry, I have to do this."  
"Who the hell are you, where the hell am I, and what did he mean by reward of all?" demanded Gabriel. "We picked up a strong soul signature in the multiverse. I was instructed by his magesty the king to bring you here and determine the source of this great power. While you were out I found that your soul's power even stronger than DETERMINATION. So the king ordered for it to be extracted and weaponized, with you along with it."  
Finishing that statement, Alphys accessed a control panel. Gabriel looked up to see needles, saws, and various other lab equipment lowering toward him. The needles injected him with a glowing neon liquid. As soon as it entered his body Gabriel felt a writhing pain, he began to scream in agony. Then Alphys powered up tesla coils carrying the same energy, and used them on Gabriel. He could feel the voltage cracking through his bones like they were shattering. "I'm so, so sorry." said Alphys.  
"I'm so gonna enjoy this." said Astelle. The guard swarmed them both as Papyrus slowly made his way towards Sans. After besting a few of the guards, Astelle sees Papyrus bear his claws.  
"Dad move!" Astelle strikes Papyrus with a fiery punch as Sans turns toward him. Then miraculously Astelle falls over. Papyrus merely scratched her, but something was off.  
"I've dosed her with noxious poison. She won't last terribly long."  
"Pap, you're a f**king monster." said Sans.  
He quickly grabbed Astelle & teleported.  
Next thing he knew they were in the capital. Sans ran door to door looking for help, but nobody would. "Dammit someone please help us! Isn't there any compassion left in this town?!" Shouted Sans. A door creaked open to his left, on the other side of it was Toriel. "Come in quick, we can help."  
Without any thought, Sans swiftly carried Astelle inside. Toriel had her placed in a bed and administered some sort of medicine to her wounds.  
" Thanks Tori, I can't thank you enough for this."  
said Sans. "My apologies, do I know you?" Says Toriel.  
" Not here but in another world, another time, I'm your husband. And that *points to Astelle* is your daughter."  
" And now Asgore has your son. " Sans turned around to see Ganz standing in the doorway.  
"But I swear; I won't let him add any more innocent people to list of lab rats. We're getting him back."  
A few days pass as Gabriel is subjected to Alphys' painful experiments. " They're coming for me, you know that don't you?" says Gabriel.  
"Your family? Yes I know, Asgore wants you to deal with them. Once the procedure is complete."  
said Alphys. " What?" Gabriel asks suspensefully.  
"It's called the Genesis Project. The construction of the perfect killing machine, a new beginning of modern warfare. I've been instructed by his magesty to weaponize this HONOR of yours. That's what we're calling it. With a new formula, we'll be able to make you stronger, faster, and more focused. At this rate, the data I've collected will allow me to make the serum compatible with anyone. An army of super-soldiers. But it needs to be tested, I'm sorry Gabriel but I have to do this for my people." said Alphys.  
"Do you? Do you think that creating the perfect weapon is what's best for your people?  
Asgore's intentions are for genocide not peace. He's broken because of what humanity did to his family now he wants them to pay. Is that what you want? Innocent lives lost because of you?! You're not a scientist or the victim. You're just a coward."  
Gabriel screams.  
Tears begin to stream down Alphys' face as she injects Gabriel with the serum. Gabriel starts screaming again as the pain resurfaces.  
Meanwhile at the safehouse, Ganz explains the situation. "Monster despise the humans here, so much in fact that a law was passed that human assistance of any kind is punishable by death."  
said Ganz.  
"Why would Asgore ever do this? He's never been so heartless." said Astelle.  
"That's just the world we live in, when the first 6 fell, Asgore had them all killed and their souls sent to Gaster. I... was the only available subject for his experiments. It took a toll on me, and Papyrus. I'm always afraid, while Pap became lifeless and cruel." Over the years Papyrus gained Asgore's interests & was placed as Captain of the Royal Guard. Lady Toriel had different views of the laws on humans, as did I and a few others. For that, we're outlaws."  
"Where would they keeping Gabriel?"said Sans.  
"And why do they want him?" said Astelle.  
"Our sources say he's in the royal lab in Hotland, apparently Alphys detected a large power source not too long ago in the space time continuum. They must have found a way to bring you here. They're trying to create weapons, enhancements. By using Gabriel's power, Asgore believes he can break the barrier and take revenge on humanity." says Ganz.  
"Which is why I'm gonna help you get him out,"  
says Undyne as she appears into the room.  
", on 1 condition. If I get you in, I want you to destroy everything you have to to prevent Asgore from his goals. After that you leave, this isn't your fight. Do we have an accord?"  
"Yeah, I think we do." said Sans."  
Back at the lab, Papyrus enters to check on Alphys. "How is the king's new pet?"  
"He has made much progress in the experiments, and has proven extremely resilient to the pain. Gabriel is in fact much stronger than anticipa.." Alphys says.  
"Gabriel? Calling it by name means that you have a bond, a bond leads to loyalty, loyalty leads to defiance. Are you defiant, snake?" Said Papyrus.  
" Wha? No I I..." As Papyrus inches towards her he swings his weapon to strike her. A hand catches it, there appeared Gabriel. His eyes were black except for his pupils which were glowing neon yellow, black glyphs on his face with no emotion on his face. Papyrus stands in shock as he tries to use his claws against Gabriel. He grabs Papyrus' hand and breaks his wrist before pushing him away from Alphys.  
"What strength! Nyehehe" cackled Papyrus. Gabriel then fires a GB point blank at Papyrus repeatedly until he leaps into the air casting several attacks at Gabriel. He dodged all of them with blinding speed. "What is this? He isn't supposed to be this strong!" Papyrus said nervously. Gabriel cast a bone clean through Paps' leg. As he fell to the ground Gabriel says, " I'm am the prodigy of your greatest treasure, and the monument to your sins. I am something buried that should never have been unearthed. I am Genesis Gabriel, and you will pay for what you have done." Papyrus falls unconscious. " Thanks for saving me, you didn't have to." said Alphys.  
"You instructed me to do so, as well as put him in his place. I will destroy all of the research as ordered and return to my kin. It's best that you leave doctor." said Gabriel.  
Meanwhile Sans & Undyne make their way through the sewers. " You sure this is the only way?" said Sans. " Unless you want to take your chances on the street with his Magesty's goons running about, yeah this is the best route. Not too far now, just around this corner and we'll be in the old labratory." As they make their way into the True Lab, Sans notices that the place seemed to have been used recently." Stop sightseeing, we got work to do. said Undyne. Boom! There was an explosion as the alarm began to sound. "What the f**k was that?!" said Sans.  
"I don't know, that wasn't part of the plan."  
said Undyne. They took the elevator upstairs to find the whole place up in flames. "Yknow what they say about using an elevator during a fire."  
said Sans.  
"Not now! We need to find your son, I think he might have something to do with this. He might have had similar ideas about Alphys' work."  
Sans & Undyne made their way to the research lab to find wounded Royal Guardsmen everywhere. At the end of the hall was Asgore, on the ground with Gabriel's boot on his neck. "I will not kill you Asgore. I am the better man, you're just a sad old fool. You ll never win this war. Not with the mistakes you've made. These people, your people will all turn on you one day, and when they do you'll regret ever seeing my face." Says Gabriel as he steps off past Sans & Undyne.  
"Your late father, we should leave this place"  
"What did they do to you Gabe?" said Sans.  
Gabriel makes his way out the front door with Sans & Undyne coming after him. More guards show up but as Sans prepares to teleport, Gabriel beats them all down at super speed. "Well that's new" said Sans.  
"We gotta move, more will be here soon." said Undyne. Sans teleport him and Undyne to the safehouse. Gabriel wasn't there at first but soon zoomed in. "Sorry kiddo, I must have botched the jump. How did you know where we were?" said Sans. "I didn't, and I must say I don't the underground's choice in interior design, the whole town has no culture." says Gabriel. In the bedroom, Toriel & Astelle are talking. Sans hugs Astelle and tells her that he's glad she's okay.  
Gabriel finds his way in, as the glyphs slowly fade from his face.  
Astelle leapt over Gabriel embracing him then hit him with an unintelligible barrage of concerned questions. He brushed it all off withe a simple "I'm fine Sis, calm down." Sans was not at all convinced. "  
" Gabe, you've been in there for days. Getting God knows what pumped into you, so please be honest with us. We're family" said Sans.  
Gabriel caved in & confessed. " Back in Horrortale, my conversation with mom triggered something in me. The power I used to break the barrier & take down evil Undyne. Alphys picked up on it & brought us here. Asgore thought it would be useful told Alphys to... run some tests. They stuck me, shocked me, cut me. By the end of it she was just as broken as me. They called my power HONOR energy. Like DT for humans, HONOR let's me run faster & hit harder. Alphys managed to enhance it. Make it more potent. She injected me with this.. serum. It hurt so much at first but, I was more powerful than ever. I could move so fast that lightning would appear slow. But, I couldn't feel anything. There was no right or wrong just... my objective. I didn't care if I killed or destroyed. They called it Project Genesis. The ultimate Super Soldier. Providing strength, Agility, and mental clarity. Meaning a living weapon, a real monster. I don't want to use that again, never."  
"I'm so sorry, we shouldn't have gone on this stupid adventure in the first place." cried Astelle.  
" It's going to be okay sis, it's over now. But I'm not backing down. The universe still needs mending and we're the only ones to do it." said Gabriel. Ganz enters and asks if they're ready to go. Sans nods and shoots a rift onto the wall for Underswap. "Thank you all for your help, win this fight y'hear?" said Sans. As the trio waved goodbye, they moved to the next AU.


End file.
